Fluid storage tank emission collection hood

ABSTRACT

An emission collection device for a fluid storage tank vent including a hood configured to completely enclose the tank vent to collect gaseous vapors emitting from the vent. The hood has at least one outlet for directing the collected vapors to a vapor collecting tank. The hood is formed of a resilient flexible material whereby if the tank is inadvertently overturned, the hood will collapse without affecting the tank shell and return to its original shape when the tank is uprighted.

United States Patent [191 Pierson [4 1 Dec. 17, 1974 FLUID STORAGE TANK EMISSION COLLECTION HOOD [75] Inventor:

[73] Assignee: Betts Machine Company, Warren,

[221 Filed: Nov. 1,1972

[21] Appl. No.: 302,841

Karl B. Pierson, Warren, Pa.

[52] US. Cl. 220/85 P, 137/382, 220/55 AN [51] Int. Cl B65d 25/00, F16] /00 [58] Field of Search..; 220/85 P, 85 VR, 85 US,

220/73, 46 MS, 46 R, 85 B, AN, DIG. l9, 220/D1G. 21, 88 R, 88 B, K; 137/377, 137/382; 141/ 52 ,290

[56] References Cited UNITED STATES PATENTS 1,291,693 l/l919 Behringer 220/73 1,894,867 l/l933 Hoffman 1,959,191 5/1934 Accy 220/55 AN 2,126,367 8/1938 Clawson et a1. 220/85 VR 2,302,234 11/1942 Marner 220/85 US 2,465,095 3/1949 Harvey 220/85 P 3,233,411 Schubert 220/85 B Primary ExaminerGeorge E. Lowrance Assistant Examiner-Allan N. Shoap Attorney, Agent, or Firm-Ba1dwin, Egan, Walling & Fetzer 57 ABSTRACT An emission collection device for a fluid storage tank vent including a hood configured to completely enclose the tank vent to collect gaseous vapors emitting from the vent. The hood has at least one outlet for directing the collected vapors to a vapor collecting tank. The hood is formed of a resilient flexible material whereby if the tank is inadvertently overturned, the

hood will collapse without affecting the tank shell and return to its original shape when the tank is uprighted.

8 Claims, 4 Drawing Figures PATENTEU 3.854.623

VIIIIIIIII FLUID STORAGE TANK EMISSION COLLECTION HOOD This invention relates to emission collection hoods and more particularly to an emission collection hood for-fluid storage tank vents.

Normally, when a tank truck is bottom loaded with gasoline, for example, at rates up to and exceeding 1,200 gallons per minute, the vapor interiorly of the tank escapes into the atmosphere by means of a vent in the top of the tank shell. Many metropolitan areas no longer permit vapor to escape into the air, but require that they be collected and returned to the storage tank. This is doneby means of an emission collection hood which fits over the vent. I

The vent is protected on top of the tank by an overturn rail. United States Department of Transportation- Regulations regarding discharge of flammable liquid state that nothing can extend above the overturn rail that can damage or rupture the tank in case of roll-over thus causingspillage. Such regulations are as follows:

(c) Overturn protection: -All closures for filling, manhole, or inspection openings shall be protected from damage which will result in leakage of lading in the event of overturning of the vehicle by being enclosed within the body of the tank or dome attached to the tank or by guards.

( l When guards are required, they shall be designed and installed to withstand a vertical load of twice the weight of the loaded tank and a horizontal load in any direction equivalent to one-half the weight of the loaded tank. These design loads may be considered independently. Ultimate strength of the material shall be used as a calculation base. If more than one guard is used each shall carry its proportionate share of the load/If protection other than guards are considered the same design load criteria is applicable.

(2) Except for pressure actuated vents no overturn protection is required for nonoperating nozzles or fittings less than 5 inches in diameter (which do not contain product while in transit) that project a distance less than the inside diameter of the fitting. This projected distance may be measured either from the shell or the top of an adjacent ring stiffener provided such stiffener is within inches of the center of the nozzle or fitting.

(3) If the overturn protection is so constructed as to permit accumulation of liquid on the top of the tank, it shall be provided with drainage facilities directed to a safe point of discharge.

Prior art in emission collection consisted of a hood made of sufficiently thick material to accommodate welding and also high enough to allow the vent to open fully. Such hoods can easily damage the tank on overturn.

There are thousands of tanks in service with overturn rails that .would not accommodate this additional height of the hood without being in violation of Department of Transportation regulations. The Department of Transportation is favorable to an emission collection hood made of fifty thousands (.050) thick aluminum as they feel that would crush without damage to the tank shell. This would not be a practical thickness to work.

with. Additionally, prior hoods lack a low'profile.

Therefore, it is an object of the invention to provide a fluid' storage tank vent vapor hood without profile limitations.

A further object of the invention is to provide a vent hood of the above type that will collapse without damage to the tank shell and will return to its original shape after being deformed or crushed.

' I A further object of the invention is to provide a vent hood of the above type that is simple in construction, economical to manufacture, and highly effective in operation.

Briefly, theforegoing objects are accomplished by the provision of an emission collection hood made from a flexible resilient material such as an elastomer (Buna- N, Viton, Polyurethane, etc. depending on the fluid being handled)'whereby it would be possible for a tank to roll over without damage to either the tank shell or the collection hood even though the hood extends above the overturn rail. A metal ring molded into the. flange section permits collapse of the hood, or stretch ing of the hood without disengaging from clamp or bolts. Y I I More specifically, the invention is directed to an emission collection device for a fluid storage tank vent including a hood configured to completely enclose the annular vent flange on the vent, such hood having a matching peripheral annular hood flange coacting with the vent flange for attaching the hood to the vent. An adjustable releasable peripheral annular clamping ring encases and clamps the two flanges together to retain the hood on the vent.

The hood flange has an annular peripheral metal re inforcing band formed in such hood flange to reinforce the same. The metal band may have gasket material on its underside, thereby enabling it to be used as a gasket.

The present .emission collection hood provides an economical means of collecting the vapors generated while filling the tank. Two outlets are provided. An end cap is provided when only one outlet is to be used.

The hood is designed to collapse in case of roll-over without adversely affecting the product retention of the cargo tank.

Other objects and advantages of the invention will be apparent from the following-description taken in conjunction with the drawings wherein:

FIG. I is a side elevational view of a fluid storage tank incorporating a vent hood of the invention;

FIG. 2 is a horizontal cross-sectional view of one of the hoods shown in FIG. 1, and showing the vent cap in dot-dash lines in raised position, and' FIG. 3 is a top plan view of the hood'shown in FIG.

FIG. 4 is an enlarged broken cross-sectional view of a portion of the hood-vent flange connection shown in FIG. 2;

Although the invention is shown and described herein with respect to transportation fluid storagetanks, it will be understood that it may be used on any fluid storage tank.

The terms and expressions which have been employed are used as terms of description, and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within'the scope of the invention claimed.

Referring to the drawings, there is shown a fluid storage tank having a top opening 12 in which is disposed a vent 14. The vent 14 has a vertical movable cap or poppet head 16 displaceable to an upper position 18.

The hood 24 has a pair ofoutlets 30, 32 for directing the collected vapors therein to an associated vapor collecting tank (not shown). The hood 24 is formed of a flexible resilient material whereby if the tank 10 is inadvertently overturned, the hood will collapse without damage to the tank shell and return to its original shape when the tank is uprighted. The resilient materialmay be a synthetic organic plastic such as a polyurethane, buna-N, or viton.

The hood 24 is secured to an associated outer peripheral annular vent flange 40 on the vent. The hood 24 has a matching peripheral annular hood flange 42 coacting with the vent flange 40 for attaching the hood to the vent. An adjustable releasable peripheral annular clamping ring 44 encases the clamps the two flanges 40 and 42 together to retain the hood 24 on the vent 14. The clamping ring is adjustably secured by a releasable clamping ring bolt 45.

The hood flange 42 has an annular peripheral metal reinforcing band 46 formed in such hood flange to reinforcethe same and function as a gasket, as aforementioned.

The tank 10 is provided with a-pair of spaced parallel overturn rails 50, 52 straddling the tank vents 14. The

such as gasoline which causes the vapors above the liquid in the tank to pass out the vent 14 such that the poppet 16 is lifted and the escaping vapors are collected in the hood 24 and thence passed out the outlets 30, 32, thence through the overturn'rails 50, 52 thence through a base 60, for example to acollecting tank, 62

1. An emission collection device for a fluid storage I tank vent comprising, a fluid storage tank'vent hood configured to completely enclose the tank'vent to collect gaseous vapors emitting from the vent, said .hood having at least one outlet for directing the collected vapors therein to an associated vapor collecting tank, said hood being formed of a flexible resilient material whereby if the tank is inadvertently overturned the hood will collapse and automatically return to its original shape when the tank is uprighted.

2. The structure of claim 1 wherein said material is a synthetic organic'plastic.

3. The structure of claim 2 wherein said synthetic organic plastic is a polyurethane.

4. The structure of claim 2 wherein saidsynthetic organic plastic is buna-N.

5. The structure of claim 2 wherein said synthetic organic plastic is viton.

6. The structure of claim l'wherein the hood is secured to an associated outer peripheral annular vent flange on the vent, said hood having a matching peripheral annular hood flange coacting with the vent flange for attaching the hood to the vent, and an adjustable releasable peripheral annular clamping ring encasing and clamping the two flanges together to retain the hood on the vent.

7. The structure of claim 6 wherein said hood flange has an annular peripheral metal reinforcing band such band to function as a gasket. 

1. An emission collection device for a fluid storage tank vent comprising, a fluid storage tank vent hood configured to completely enclose the tank vent to collect gaseous vapors emitting from the vent, said hood having at least one outlet for directing the collected vapors therein to an associated vapor collecting tank, said hood being formed of a flexible resilient material whereby if the tank is inadvertently overturned the hood will collapse and automatically return to its original shape when the tank is uprighted.
 2. The structure of claim 1 wherein said material is a synthetic organic plastic.
 3. The structure of claim 2 wherein said synthetic organic plastic is a polyurethane.
 4. The structure of claim 2 wherein said synthetic organic plastic is buna-N.
 5. The structure of claim 2 wherein said synthetic organic plastic is viton.
 6. The structure of claim 1 wherein the hood is secured to an associated outer peripheral annular vent flange on the vent, said hood having a matching peripheral annular hood flange coacting with the vent flange for attaching the hood to the vent, and an adjustable releasable peripheral annular clamping ring encasing and clamping the two flanges together to retain the hood on the vent.
 7. The structure of claim 6 wherein said hood flangE has an annular peripheral metal reinforcing band formed in such hood flange to reinforce the same.
 8. The structure of claim 7 wherein said metal band has gasket material on its underside thereby enabling such band to function as a gasket. 